learnt the stay to be found in the depth of the hour of bitterness, and the remembrance that restrains the soul at the coming of the moment of delight, giving it a more conscious welcome, but presaging for it an inexorable flight.  And “rarely, rarely comest thou,” sighed Shelley, not to Delight merely, but to the Spirit of Delight.  Delight can be compelled beforehand, called, and constrained to our service—­Ariel can be bound to a daily task; but such artificial violence throws life out of metre, and it is not the spirit that is thus compelled. That flits upon an orbit elliptically or parabolically or hyperbolically curved, keeping no man knows what trysts with Time.

It seems fit that Shelley and the author of the “Imitation” should both have been keen and simple enough to perceive these flights, and to guess at the order of this periodicity.  Both souls were in close touch with the spirits of their several worlds, and no deliberate human rules, no infractions of the liberty and law of the universal movement, kept from them the knowledge of recurrences. Eppur si muove.  They knew that presence does not exist without absence; they knew that what is just upon its flight of farewell is already on its long path of return.  They knew that what is approaching to the very touch is hastening towards departure.  “O wind,” cried Shelley, in autumn,

   O wind,
   If winter comes can spring be far behind?

They knew that the flux is equal to the reflux; that to interrupt with unlawful recurrences, out of time, is to weaken the impulse of onset and retreat; the sweep and impetus of movement.  To live in constant efforts after an equal life, whether the equality be sought in mental production, or in spiritual sweetness, or in the joy of the senses, is to live without either rest or full activity.  The souls of certain of the saints, being singularly simple and single, have been in the most complete subjection to the law of periodicity.  Ecstasy and desolation visited them by seasons.  They endured, during spaces of vacant time, the interior loss of all for which they had sacrificed the world.  They rejoiced in the uncovenanted beatitude of sweetness alighting in their hearts.  Like them are the poets whom, three times or ten times in the course of a long life, the Muse has approached, touched, and forsaken.  And yet hardly like them; not always so docile, nor so wholly prepared for the departure, the brevity, of the golden and irrevocable hour.  Few poets have fully recognized the metrical absence of their muse.  For full recognition is expressed in one only way—­silence.